Wassup fellas I built a box for a 18 btl but went with an aq hdc3 18 until Christmas. It is 8 ft3 at 30 hz. My problem is I think this box it too big for the hdc because anything above 40 hz sounds like trash but is a low end monster! also from 25 hz to 40 hz the excursion is the same! It's like the box is too big and it's acting like IB. Can some one help me out ha I want an ok topend instead of the junk I have know! Thanks

What's your low pass filter set at?

It's set at about 65 I've played with that a good bit it's just that sounds dirty as hell and is not tight.

Also it seems that it's not tuned, I know it is but I see about 2 inches of excursion at full power from 40hz to 25

Of course it won't do good on the higher notes.. It's tuned so low... If you Want there to be better higher notes you need to tune higher..

I thought people run low tunes for sound quality, I'm not looking for spl up higher but it sounds slow and sloppy like as if it didn't have control. If I take a cubic foot out of the box to put it back with in manufact specs would it be more tight? Also would it raise my tuning?

Bootybump!

If you take off some volume inside the box, and keep the same port, it should lower your tuning. If I understood it correctly.

Try to put some wood, or anything, to take some room off the box and test, test, test it !

If you take off some volume inside the box, and keep the same port, it should lower your tuning. If I understood it correctly.

Try to put some wood, or anything, to take some room off the box and test, test, test it !

No Sir.

The smaller the net volume, assuming the port dimensions are unchanged, the higher the box tuning.

That the answer I was looking for! So would taking a cubic foot out make it more snappy and tight? Also the box is 1 cubic foot over spec. But all this still doesn't explain why I can't physically see the tuning frequency all oft other boxes I was able to see it. Thanks for the replies guyz!!!

I thought people run low tunes for sound quality, I'm not looking for spl up higher but it sounds slow and sloppy like as if it didn't have control. If I take a cubic foot out of the box to put it back with in manufact specs would it be more tight? Also would it raise my tuning?

Tuning an enclosure low does not necessarily mean its being tuned for sound quality ... That large of a enclosure with a low tuned port may make the enclosure "unload" at low frequencies for a high spl reading ... My enclosure was built to minimum space allowed for each sub ... Then added port for a flat response low tuning ...

1.8 cu ft with 40 in of port, 4 in pvc (I think) ...

There a lot more to it but that's the basic principle ...

Just my suggestion here sir ... Hope this helps some ...

Thanks, Randal ...

Well the reason I said they run low tunes for sound quality was because having a low tune usually gives a flat response, I think haha! Thanks for the explanation randal, you've helped me through a few of my questions in the past as well. Do you guyz have any suggestions as to take up space, I'm thinkIn foam in a can?

Wood to take up space.

Wood ... Spare mdf

Well how would y'all recommend puttin it in the enclosure

Pics of enclosure would help with this ...

Is there a way I could post with an I phone? If not I can when I get home at 5

Pics won't help, but they're nice to look at.

What is your net volume, port dimensions, overall (gross) volume and thickness of the walls?

i built a box for an AQ hdc3 15 few yrs ago that was 8cuft tuned to 29hz. It's like i'm reading my own post, lol.

Anything over 40hz was terrible...

Reason-

AQ HDC3 is a PEAKY sub. Therefore, you shouldnt have built the box as big if you wanna keep that sub.

The BTL, cant remember off top of my head, but definitely isnt as peaky as the HDC3 is.

A 15" HDC3 needs to be in 4-4.5cuft tops for typical playback tuned at 35hz or higher.

Any lower than 35hz regardless of volume unless below ~3.5cuft rolls off upper notes too soon.

I looked at this on BBP6 and with The recommended minimum port, 14" in diameter and 51" long, it is has a very flat response.

However, if I add cabin gain starting at 50 hertz with a 3 DB rise, you wind up with an 11 DB peak at 25 hertz.

You are only 3 DB up at 50 hertz.

This doesn't mean much in your vehicle, but could be part of the problem you have described, if this is a lack of output.

If it has plenty of output but sounds bad, it could be something else.

It sound like Shizzzzon has confirmed my thoughts.

I had the same issue with 4 SA-8's.

From 50 hertz to 30 they were monsters, but above that, nothing.

I was allot happier with around .25 C.F. per sub than the .8 C.F. that was in the middle of what was recommended for the subs.

The were peaky.

My dash bouncing up and down would agree.

ha wow yall thanks for the replys i got pics coming up soon! so i got bored and took about 5 10in long 2x4's and screwed them to the inside of the box, it was like a whole new sub, it defintely picked up around the 40hz area a good bit as to know it is hurting my ears pretty bad if i turn it up, and i can hear the 45hz up to 65hz well and semi clear! tommorow i will take the sub back out and double the amount of 2x4's and see what happens. thanks again

- Clint

ha wow yall thanks for the replys i got pics coming up soon! so i got bored and took about 5 10in long 2x4's and screwed them to the inside of the box, it was like a whole new sub, it defintely picked up around the 40hz area a good bit as to know it is hurting my ears pretty bad if i turn it up, and i can hear the 45hz up to 65hz well and semi clear! tommorow i will take the sub back out and double the amount of 2x4's and see what happens. thanks again

- Clint

By any chance you planning on making this event ??? I you are, let me know so we can meet up ...

Chillaxin' in Jackson ... 08/20/11 ... start time 2:00 pm ... at the trade mart center ...

USACI Mississippi State Regionals ...

I will know for sure about a week before it, im going on a week long trip to spring river starting sunday so it's gonna suck my gas money and spare money funds super low so I gotta see if I'll be able to afford the fuel. I'll pm you if I can make it.